Open Access. Powered by Scholars. Published by Universities.®

Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

2017

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 871 - 900 of 1882

Full-Text Articles in Biology

Characterization Of Newly Created Mitochondrial Genes Affecting Drosophila Melanogaster Sperm Phenotypes Through Genetic Manipulation, Makayla Dearborn May 2017

Characterization Of Newly Created Mitochondrial Genes Affecting Drosophila Melanogaster Sperm Phenotypes Through Genetic Manipulation, Makayla Dearborn

Renée Crown University Honors Thesis Projects - All

Reproductive traits, including phenotypes related to sperm form and function, frequently evolve rapidly under the influence of strong sexual selection. Understanding the genetic basis of this process is of paramount importance to evolutionary biologists and has important implications on our understanding of reproductive outcomes and fertility. The creation of new genes is suspected to contribute to this process as new genes are often expressed in the testis. However, little is currently known about how, and if, these genes acquire novel functions in spermatogenesis. Many novel genes are retrogenes. Retrogenes are formed through reverse transcription of mRNA. A set of retrogenes …

Go to article

Measuring The Presence Of The Amphibian Pathogen Batrachochytrium Dendrobatidis In East Tennessee, Erin A. Schrenker May 2017

Measuring The Presence Of The Amphibian Pathogen Batrachochytrium Dendrobatidis In East Tennessee, Erin A. Schrenker

Honors Theses

I examined the presence and absence of the amphibian pathogen Batrachochytrium dendrobatidis in three survey areas in Eastern Tennessee. Amphibians were swabbed to assess for Bd and other ecological qualities like canopy cover, and air and water temperature are a few of the measurements evaluated. DNA was extracted from the swabs using a Qiagen DNeasy Blood and Tissue Kit and samples were PCRed in triplicate to confirm presence or absence. All 48 animals that were swabbed in the field were negative for Bd. These results parallel other findings that few Bd positive assays have been conducted in East Tennessee from …

Go to article

Prevalence Of Batrachochytrium Dendrobatidis (Bd) In Watercourses Situated In Southeast Tennessee, Macall A. Nabors May 2017

Prevalence Of Batrachochytrium Dendrobatidis (Bd) In Watercourses Situated In Southeast Tennessee, Macall A. Nabors

Honors Theses

Four hundred and twenty-seven amphibian species are critically endangered. The fungal disease Batrachochytrium dendrobatidis (Bd) has been correlated with amphibian decline and extinction. Numerous studies concerning the nature of Bd have been conducted; however, additional studies are needed to adequately evaluate Bd in southeastern Tennessee. As a result of previous studies, the following hypothesizes were proposed: watercourses in southeastern Tennessee will test positive for Bd, non-impacted streams will have a greater presence of Bd than impacted streams, and increased canopy coverage has a positive correlation with the presence of Bd. Field sampling took place from June 2nd 2016 to August …

Go to article

Assessment Of Long-Term Effects Of Woody Plants Expansion In Humid, Tropical Grassland Of Venezuela, Soraya A. Delgado May 2017

Assessment Of Long-Term Effects Of Woody Plants Expansion In Humid, Tropical Grassland Of Venezuela, Soraya A. Delgado

Theses and Dissertations

The invasion of woody plants into grassland communities, or shrub encroachment, is a worldwide phenomenon usually attributed to anthropogenic interference. Most studies have focused on temperate and arctic biomes. Less is known about how shrub encroachment is affecting humid tropical grasslands, which have different climates, higher levels of biodiversity and different histories of human land use. This project quantifies the rate of woody vegetation change in a humid tropical grassland of Venezuela using remote sensing over the past quarter century and ground based measurements of selected individual species. Results of remote sensing indicate high rates of conversion of grasslands to …

Go to article

Thylakoid Protein Targeting/Insertion By A Signal Recognition Particle In Chloroplasts, Priyanka Sharma May 2017

Thylakoid Protein Targeting/Insertion By A Signal Recognition Particle In Chloroplasts, Priyanka Sharma

Graduate Theses and Dissertations

Protein targeting is a fundamental cellular process that directs proteins from their site of synthesis to the site where they function. The signal recognition particle (SRP) dependent targeting pathway is conserved in both eukaryotes and prokaryotes where it co-translationally targets polypeptide chains emerging from ribosomes to the endoplasmic reticulum (eukaryotes) or cytoplasmic membrane (prokaryotes). A structurally unique form of SRP is found in chloroplasts where it functions to post-translationally bind and target a subset of integral thylakoid membrane proteins, the light harvesting chlorophyll binding proteins (LHCPs). Mature LHCPs bind chlorophyll a/b and function in photosynthetic light capture. Like many other …

Go to article

Chronic Arsenic Exposure In Nanomolar Concentrations Accelerates Senescent Phenotypes In Vitro, Heather M. Sabo May 2017

Chronic Arsenic Exposure In Nanomolar Concentrations Accelerates Senescent Phenotypes In Vitro, Heather M. Sabo

Biological Sciences

Arsenic is recognized as an environmental carcinogen, in which over 100 million individuals worldwide experience chronic exposure through contaminated drinking water. Arsenic exposure is linked to several health conditions, such as cancer, diabetes, skin lesions, immune dysfunction, and cardiovascular disease. Here we test the hypothesis that toxicants, such as arsenic, accelerate the program of senescence. Human (IMR-90) primary diploid fibroblasts were chronically exposed to arsenic at nanomolar concentrations and the impact on the expression of senescent-associated mRNAs was evaluated. IMR-90 cells were exposed either to untreated media or exposed to 130nM and 330nM AsCl3 supplemented media. RNA samples were extracted …

Go to article

Exploration Of The Interactions Between Amyloid-Beta Protein And Insulin In Various Ionic Conditions, Quade Goldenberg May 2017

Exploration Of The Interactions Between Amyloid-Beta Protein And Insulin In Various Ionic Conditions, Quade Goldenberg

Biological Sciences

Alzheimer’s disease (AD) is characterized by tau tangles and amyloid - β (Aβ) peptide aggregates amyloids in the brain, specifically in the hippocampus. Aβ plaques are known to form primarily in the extracellular space aroun d neuronal cells, interfering with synaptic transmission. The aggregation of Aβ in the hippocampus is associated with a decline in hippocampally - mediated cognitive abilities, which is a symptom of AD. AD has a strong correlation to type 2 diabetes mellitus (T2DM), which is defined by hyperinsulinemia and dysregulated glucose metabolism. It has been shown that insulin plays a role in both memory and learning …

Go to article

Mulitmodal Molecular Mechanisms Control Germline Stem Cell Differentiation In Drosophila, Mohamad Nasrallah May 2017

Mulitmodal Molecular Mechanisms Control Germline Stem Cell Differentiation In Drosophila, Mohamad Nasrallah

Biological Sciences

Stem cells have the intrinsic ability to divide to form a stem cell daughter, while also retaining the ability to self - renew. These qualities are critical , as improper stem cell maintenance is implicit in aging and provokes diseases such as cancer. We previously revealed that during Drosophila oogenesis, transcriptional silencing mediated by polar granule component (pgc) alters the germ line cell cycle to promote germ line stem cell (GSC) differentiation. O ur work with pgc suggested that cell cycle regulation might be an important general mecha nism to facilitate division GSCs into daughter stem cells (or cystoblast, CBs), …

Go to article

Bhlhe40-As1 A Long-Noncoding Rna Regulates Dec1 On Breast Cancer Progression, Denisse Duran-Reyes May 2017

Bhlhe40-As1 A Long-Noncoding Rna Regulates Dec1 On Breast Cancer Progression, Denisse Duran-Reyes

Biological Sciences

Ductal Carcinoma in Situ (DCIS) is a precursor to breast cancer where abnormal cells have been found in the mammary duct but have not become invasive and spread into surrounding tissue. There has been an increase in early diagnosis of DCIS, but only around 40% of the cases ever progress to an invasive stage, and thus detection can lead to unnecessary surgeries. To identify which of these 40% progress, long noncoding RNAs were used. Through RNA sequencing of DCIS and invasive cells from real patient samples, BHLHE40 - AS1 was discovered, a long - noncoding R NA, to be highly …

Go to article

Controllable And Sequential Activation Of Cancer Nanotherapy For Enhanced Synergistic Effec, Vincent E. Lamantia May 2017

Controllable And Sequential Activation Of Cancer Nanotherapy For Enhanced Synergistic Effec, Vincent E. Lamantia

Biological Sciences

The treatment of numerous disease states has become increasingly more complex and challenging, even as we come out with new pharmacological and technological advancements. It is well known that cancer is not one disease, but many diseases that progress and present new challenges with each patient. With this we present a novel design which uses biorthogonal chemistry and magnetic nanoparticles (MNP’s) to create a drug delivery system with the capability to deliver two drugs that are released at two different time points under the direction of a single trigger. This innovative combination of multiple advancements will allow for the treatment …

Go to article

Transcriptional Regulation Of Dksa P3 Promoter In Escherichia Coli, Chibuokem Ikwuazom May 2017

Transcriptional Regulation Of Dksa P3 Promoter In Escherichia Coli, Chibuokem Ikwuazom

Biological Sciences

DksA, a global gene regulator, binds to RNA po lymerase to regulate transcription initiation in Escherichia coli . It negatively regulates transcription of some genes, such as those for ribosomal RNAs and fis , and positively regulates transcription of other genes, including genes involved in amino acid biosynthesis. Little is known about how DksA itself is regulated. Current work in our lab has shown three major promoters, a σ 70 dependent P 1 promoter and two σ 38 (RpoS) - dependent promoters (P 2 and P 3 ), regulate the transcription of dksA . More is current ly known about …

Go to article

Applications Of Side Scan And Parametric Echosounders For Mapping Shallow Seagrass Habitats And Their Associated Organic Carbon, Austin L. Greene May 2017

Applications Of Side Scan And Parametric Echosounders For Mapping Shallow Seagrass Habitats And Their Associated Organic Carbon, Austin L. Greene

Theses and Dissertations

Despite a global valuation of $1.9 trillion seagrass habitats world-wide are in decline—directly impacting the large soil carbon stocks associated with seagrasses. Many methods exist to measure the health of seagrass habitats, yet few apply to shallow coastal ecosystems. Those that do lack spatial resolution (satellite surveys) or do not provide continuous data across large areas (point-based surveys). Furthermore, carbon content of these ecosystems is largely limited to destructive and time-consuming soil core sampling. Side scan and parametric acoustics represent a unique technological opportunity to study habitat coverage and carbon content of vegetated coastal habitats (< 3 m depth). This study presents proof of concept for applications of recreational side scan and parametric sub-bottom profiling sonars in mapping both habitat coverage and organic carbon distribution in shallow seagrass habitats, and explores how these methods might be improved in future applications.

Go to article

Decomposition Of Black Mangrove (Avicennia Germinans ) Leaf Litter: Calibrating Estuarine Indicators Of Functional Recovery, Leticia Martinez Contreras May 2017

Decomposition Of Black Mangrove (Avicennia Germinans ) Leaf Litter: Calibrating Estuarine Indicators Of Functional Recovery, Leticia Martinez Contreras

Theses and Dissertations

Decomposition of plant material produced by mangroves and other macrophytes in estuaries occurs in both sediments and the water column. Early and intense processing could be more common in the water. In a previous study, in situ decomposition rates of Black Mangrove (Avicennia germinans ) leaf litter suspended in the water column differed among three estuaries in south Texas with moderate differences in salinity, water temperature, available nitrogen (N), and tidal flow. A series of microcosm experiments were conducted to determine the influence, within observed ranges in the estuaries, of these water variables on mass loss of Black Mangrove …

Go to article

Genetic Variation In Two Economically Important Arthropod Vectors Of Citrus Diseases, Alejandra Fuentes May 2017

Genetic Variation In Two Economically Important Arthropod Vectors Of Citrus Diseases, Alejandra Fuentes

Theses and Dissertations

Arthropod vectors are agriculturally and ecologically important because they transmit numerous plant pathogens. Commonly, control strategies for vector-borne plant pathogens focus on suppression of vector populations. Genetic variation studies in pest populations provide useful information for biological control, understanding pesticide resistance, and inferring global movement patterns. In chapter I, genetic variation of worldwide populations of Diaphorina citri, the vector of Citrus greening disease, was examined to assess potential sites of origin of invasive populations. The results showed population structure at regional levels, suggesting limited gene flow and revealing patterns of invasion. In chapter II, I explored the community of …

Go to article

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett May 2017

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett

Electronic Theses and Dissertations

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With …

Go to article

Inclusive Teaching Strategies: An Evaluation Of Course Structure And Summative Assessment In Introductory Biology, Oluwaseun O. Agboola May 2017

Inclusive Teaching Strategies: An Evaluation Of Course Structure And Summative Assessment In Introductory Biology, Oluwaseun O. Agboola

Electronic Theses and Dissertations

Several active learning strategies have been used when increasing the structure of a course as increasing course structure has been known to improve student learning in introductory STEM courses. Much has been studied on the value of frequent formative assessment; however, few studies have evaluated the effective modes of delivering summative assessment. This study examines the use of summative assessment as an inclusive teaching practice to improve first generation college student success in introductory biology and also uses faculty surveys to find out how instructors structure their introductory biology course and why they are structured that way. Final exams were …

Go to article

Effects Of Predatory Cues On Copper Sensitivity And Metabolic Rate In Gambusia Affinis, Melissa N. Campbell May 2017

Effects Of Predatory Cues On Copper Sensitivity And Metabolic Rate In Gambusia Affinis, Melissa N. Campbell

Electronic Theses and Dissertations

Organisms living in aquatic environments are subject to a number of stressors from natural (temperature, predation, food availability) and anthropogenic origins (pesticides, metals, etc). Natural stressors may amplify the effects of contaminants and increase an organism’s sensitivity to them. Understanding the impact of these combined factors is therefore essential for the practical management of contaminants. This study sought to examine how predatory cues affect copper tolerance in the mosquitofish, Gambusia affinis. The influence of predatory cues on fish metabolic rate was also evaluated to gain insight on any interactive effects between the natural stressor and copper. Alarm cues, chemicals released …

Go to article

A Variant Pfcrt Isoform Can Contribute To Plasmodium Falciparum Resistance To The First-Line Partner Drug Piperaquine, Satish K. Dhingra, Devasha Redhi, Jill M. Combrinck, Tomas Yeo, John Okombo, Philipp P. Henrich, Annie N. Cowell, Purva Gupta, Matthew L. Stegman, Jonathan M. Hoke, Roland A. Cooper, Elizabeth Winzeler, Sachel Mok, Timothy J. Egan, David A. Fidock May 2017

A Variant Pfcrt Isoform Can Contribute To Plasmodium Falciparum Resistance To The First-Line Partner Drug Piperaquine, Satish K. Dhingra, Devasha Redhi, Jill M. Combrinck, Tomas Yeo, John Okombo, Philipp P. Henrich, Annie N. Cowell, Purva Gupta, Matthew L. Stegman, Jonathan M. Hoke, Roland A. Cooper, Elizabeth Winzeler, Sachel Mok, Timothy J. Egan, David A. Fidock

Biological Sciences Faculty Publications

Current efforts to reduce the global burden of malaria are threatened by the rapid spread throughout Asia of Plasmodium falciparum resistance to artemisinin-based combination therapies, which includes increasing rates of clinical failure with dihydroartemisinin plus piperaquine (PPQ) in Cambodia. Using zinc finger nuclease-based gene editing, we report that addition of the C101F mutation to the chloroquine (CQ) resistance-conferring PfCRT Dd2 isoform common to Asia can confer PPQ resistance to cultured parasites. Resistance was demonstrated as significantly higher PPQ concentrations causing 90% inhibition of parasite growth (IC90) or 50% parasite killing (50% lethal dose [LD50]). This mutation …

Go to article

Assessment Of The Calling Detection Probability Throughout The Day Of Two Invasive Populations Of Bullfrog (Lithobates Catesbeianus) In Uruguay, Gabriel Laufer, Noelia Gobel, Alvaro Soutullo, Claudio Martinez-Debat, Rafael O. De Sá May 2017

Assessment Of The Calling Detection Probability Throughout The Day Of Two Invasive Populations Of Bullfrog (Lithobates Catesbeianus) In Uruguay, Gabriel Laufer, Noelia Gobel, Alvaro Soutullo, Claudio Martinez-Debat, Rafael O. De Sá

Biology Faculty Publications

Bullfrog invasion is a major conservation concern in South America, so there is an urgent need to detect and monitor its many invasion foci. Amphibian sampling methods commonly use calling display, specifically the nuptial calls of males. With the aim of obtaining the better day period to sample and monitor Lithobates catesbeianus presence, we recorded its calls at three ponds in two invaded localities in Uruguay (Aceguá, Cerro Largo, and San Carlos, Maldonado) during the reproductive season. Then, we studied the records, obtaining a subsample of calling intensity at the first 5 minutes for each hour. We detected that vocalization …

Go to article

The Role Of The Diras Family Members In Regulating Ras Function, Cancer Growth And Autophagy, Margie Nicole Sutton May 2017

The Role Of The Diras Family Members In Regulating Ras Function, Cancer Growth And Autophagy, Margie Nicole Sutton

Dissertations and Theses (Open Access)

DIRAS3 is a maternally imprinted tumor suppressor gene that is downregulated by multiple mechanisms across several tumor types. When re-expressed, DIRAS3 decreases proliferation, inhibits motility, and induces autophagy and tumor dormancy. DIRAS3 encodes a 26 kDa small GTPase with 60% homology to Ras and Rap, differing from oncogenic Ras family members by a 34-amino acid N-terminal extension that is required for its tumor suppressive function in ovarian cancer. By assessing the structure-function relationship, I found that DIRAS3 inhibits Ras-induced transformation and is a natural antagonist of Ras/MAPK signaling. DIRAS3 binds directly to Ras and disrupts cluster formation inhibiting the activation …

Go to article

Proteomic Identification Of Histone Post-Translational Modifications Induced By Dna Double-Strand Breaks And Novel Proteins Involved In The Dna Damage Response, Pingping Wang May 2017

Proteomic Identification Of Histone Post-Translational Modifications Induced By Dna Double-Strand Breaks And Novel Proteins Involved In The Dna Damage Response, Pingping Wang

Dissertations and Theses (Open Access)

Inaccurate repair of DNA double-strand breaks (DSBs) can lead to DNA mutation and chromosome rearrangements, causing human diseases such as cancer. Although we know the basic mechanisms of DSB repair, the added complexities in the chromatin context are unclear. This is partially due to the lack of unbiased systems for identifying proteins and post-translational modifications (PTMs) involved in DSB repair. In this work, we established a novel method, termed DSB-ChAP-MS (Double Strand Break-Chromatin Affinity Purification with Mass Spectrometry), for the affinity purification of a sequence-specific single copy endogenous chromosomal locus containing a DSB, followed by the proteomic identification of enriched …

Go to article

Characterization Of The Ubiquitin Ligase, Ube4b, In Endocytic Trafficking, Natalie Sirisaengtaksin, Natalie Sirisaengtaksin May 2017

Characterization Of The Ubiquitin Ligase, Ube4b, In Endocytic Trafficking, Natalie Sirisaengtaksin, Natalie Sirisaengtaksin

Dissertations and Theses (Open Access)

Endocytosis is a process by which cells internalize membrane proteins to remove them from the plasma membrane, allowing cells to regulate the cell surface expression of transmembrane proteins. In this manner, cellular responses to extracellular cues may be tuned by limiting the number of proteins available at the cell surface. One particular class of proteins, receptor tyrosine kinases (RTK), is internalized upon binding to extracellular ligands during their residence at the cell surface. The epidermal growth factor receptor (EGFR) is an RTK whose trafficking through the endocytic pathway through the cell is well-documented. Stimulation of EGFR with its cognate ligand, …

Go to article

Behavioral Plasticity Across Non-Social Contexts In Female Green Swordtails, Xiphophorus Helleri, Lindsey M. Coit May 2017

Behavioral Plasticity Across Non-Social Contexts In Female Green Swordtails, Xiphophorus Helleri, Lindsey M. Coit

School of Biological Sciences: Dissertations, Theses, and Student Research

Phenotypic plasticity is the ability of an individual to alter its phenotype in response to environmental change. Individuals that express plasticity in behavior can quickly respond to changes that occur in the environment. Therefore, individuals that exhibit behavioral plasticity can alter their behavioral expression to best match current environmental conditions. The degree and direction of behavioral plasticity may be influenced by variation in individual characteristics. Understanding how variation in individual traits affects behavioral plasticity, and, whether patterns of behavioral plasticity are consistent across behavioral contexts are important topics to explore as we try to better understand how plasticity evolves and …

Go to article

Variation In Density Dependent Seedling Survival Across Forests Of Different Successional Age And Hunting Protection Status, Nohemi Huanca-Nunez May 2017

Variation In Density Dependent Seedling Survival Across Forests Of Different Successional Age And Hunting Protection Status, Nohemi Huanca-Nunez

School of Biological Sciences: Dissertations, Theses, and Student Research

Over 50% of the original extent of tropical forests has been cleared. Restoration of secondary forests is important for maintaining the ecosystem services that mature tropical forests provide. Density dependence (DD) is thought to be a major mechanism for shaping forest community structure and may cause reduced spatial aggregation among individuals of the same species, allowing for maintenance of diversity. While much research has focused on DD in mature tropical forests, few studies have examined how DD may influence community structure in secondary forests, many of which are also exposed to hunting. There are several important agents of negative and …

Go to article

Toll Like Receptor 4 Stimulation Increases Scavenger Receptor A Expression On Murine Macrophages, Mackenzie L. Guthrie May 2017

Toll Like Receptor 4 Stimulation Increases Scavenger Receptor A Expression On Murine Macrophages, Mackenzie L. Guthrie

Undergraduate Honors Theses

Sepsis is the body’s response to an overwhelming infection and is a serious consequence of critical illness. It can cause tissue damage, organ failure, and death. Sepsis continues to have an unacceptably high mortality rate, due to the lack of effective treatments. Specific therapeutic targets for sepsis remain elusive since the complex functional changes that result in a septic state remain poorly understood. Macrophage Scavenger Receptor A (SRA, CD204) is a surface receptor that binds negatively charged, endogenous and exogenous ligands. We have discovered that SRA plays a significant role in the pathophysiology of sepsis. We have shown that mice …

Go to article

Role Of Ime4 And Pho92 Proteins In Pho5 Regulation, Krishna Shah May 2017

Role Of Ime4 And Pho92 Proteins In Pho5 Regulation, Krishna Shah

Senior Honors Theses

In the yeast Saccharomyces cerevisiae, m6A methylation regulates the stability and translation of mRNA. Ime4, which is highly active in meiotic cells, recognizes consensus methyl sites in pre-mRNA and adds methyl groups to a small fraction of adenosine residues, whereas Pho92 binds to such methylated sites and promotes subsequent degradation. PHO5 transcripts expression is upregulated when IME4 and PHO92 are deleted. In the PHO5 transcript, near the stop codon of the open reading frame (ORF), there is a potential consensus methyl site that is predicted to be methylated, based on its location and excellent match to the consensus methylation sequence …

Go to article

The Role Of The Fatty Acid Signaling Pathway In Dietary-Induced Obesity, Melissa N. Nelson May 2017

The Role Of The Fatty Acid Signaling Pathway In Dietary-Induced Obesity, Melissa N. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In recent years, dietary fat has been shown to be capable of activing taste receptor cells in the tongue. Fatty acids (FAs), which act as the chemical cue and are found in dietary fat, activate a cellular signaling pathway that results in a unique signal being sent to the brain that is then interpreted as the taste of fat. One important element in this pathway is the ion channel TrpM5. It is responsible for depolarizing the taste cells that are activated by fatty acids; depolarization is an essential step in cellular response, making TrpM5 essential in the functioning of the …

Go to article

Vegetation Community Changes In Two National Forests In The Pineywoods, East Texas, Trisha L. Williams May 2017

Vegetation Community Changes In Two National Forests In The Pineywoods, East Texas, Trisha L. Williams

Electronic Theses and Dissertations

Despite extensive research into forest succession, little research has been directed to long-term studies. The fundamental properties of succession remain unclear and further research into terrestrial vegetation and an accounting of drivers in specific ecosystem types is required. This study addresses change in plant communities from five ecosystem types in two east Texas National Forests over a 20-year period. An analysis of 30 sample stands yields results due to various ecosystem drivers of vegetation change and uncovers plant community responses in multiple ecosystem types over this period. This research provided three key results: 1) that vegetation composition change occurs more …

Go to article

Increasing Marine Debris Awareness Through Public Education And Analyzing Fish For Microplastic And Pollutant Contamination, Stephanie R. Dubois May 2017

Increasing Marine Debris Awareness Through Public Education And Analyzing Fish For Microplastic And Pollutant Contamination, Stephanie R. Dubois

Theses and Dissertations

Marine debris is any persistent solid material that is manmade and then disposed of into the world’s oceans. Outreach and education was used in combination with biological research using an indicator fish species to raise awareness about the impacts of marine debris and encourage change in behavior to reduce marine debris. Pre and post surveys were administered during marine debris education tours for K-12 students at the Coastal Studies Lab on South Padre Island, Texas to determine change in knowledge and behavior regarding marine debris. Pinfish were collected from Laguna Madre and stomachs and livers removed for microplastics content and …

Go to article

L-2-Hydroxyglutarate Production Arises From Non-Canonical Enzyme Function At Acidic Ph, Andrew M. Intlekofer, Bo Wang, Hui Liu, Hardik Shah, Carlos Carmona-Fontanie, Ariën S. Rustenburg, Salah Salah, Marilyn R. Gunner, John D. Chodera, Justin R. Cross, Craig B. Thompson May 2017

L-2-Hydroxyglutarate Production Arises From Non-Canonical Enzyme Function At Acidic Ph, Andrew M. Intlekofer, Bo Wang, Hui Liu, Hardik Shah, Carlos Carmona-Fontanie, Ariën S. Rustenburg, Salah Salah, Marilyn R. Gunner, John D. Chodera, Justin R. Cross, Craig B. Thompson

Publications and Research

The metabolite 2-hydroxyglutarate (2HG) can be produced as either a D(R)- or L(S)- enantiomer, each of which inhibits alpha-ketoglutarate (αKG)-dependent enzymes involved in diverse biologic processes. Oncogenic mutations in isocitrate dehydrogenase produce D-2HG, which causes a pathologic blockade in cell differentiation. On the other hand, oxygen limitation leads to accumulation of L-2HG, which can facilitate physiologic adaptation to hypoxic stress in both normal and malignant cells. Here we demonstrate that purified lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) catalyze stereospecific production of L-2HG via ‘promiscuous’ reduction of the alternative substrate αKG. Acidic pH enhances production of L-2HG by promoting a …

Go to article

First Prev Next Last